This article does not refer to the made-in-China Spirit guitar sold under the Gibson Baldwin Music Education nameplate.

All spirits have a double-cutaway design, with the upper horn slightly longer than the lower.

Early models are said to have poplar bodies, with later ones being produced in mahogany or alder, some with maple tops.

A custom shop version of a red Spirit XPL with one humbucker, a Kahler/Gibson tremolo bridge that used standard Gibson bridge posts, and body binding but no neck binding was observed on eBay in July/August 2010 bearing a 1983 serial number.

The SR-71 has a bolt-on neck, Floyd Rose tremolo, S/S/H pickups, and took on more of a Strat shape.

The guitar was actually designed by a member of the Charvel family who had no affiliation with the Jackson/Charvel company at the time.

The auction included the original Gibson invoice with Hayes's name and shipping address, as well as a letter of appraisal from vintage guitar expert George Gruhn.

The guitar's humbuckers had been changed to rail types, and the tremolo system was a floating Kahler style that used standard Gibson adjustable bridge posts, rather than the production Flyer tremolo that mounts to the body with a trim ring.

The guitar's serial number identified it as a very early 1985 model, and included an "Original Gibson Prototype" stamp screened on the back of the headstock.